6.7L Power Stroke Engine and Drivetrain
Discussion of the 6.7L Power Stroke diesel engine and drivetrain in the 2011-Up Super Duty trucks. No gas engine discussion allowed except on transmissions and drivetrain that pertain to all models. Please confine discussion of topics in this forum to those items that are specific to the 6.7L Power Stroke engine.

Used my 4x4 today for the first time with the snow that we received. It is normal to have some hop and actually have feedback from the system kind of like you can actually feel the universal joints fighting the turn? I didn't have this feeling as much with my GMC. The truck really felt like it didn't want to turn and the front wanted to slide more than I thought it would. This was at parking lot speeds and turning into my garage.

It's normal. With any 4X4 that locks the transfer case in the tires have to slip or scoot to compensate for the difference in wheel speed when turning. How severe it is will vary with different vehicles due to things like, wheel base, vehicle weight and turning radius.

GM's are different because they have CV (Constant Velocity) joints as opposed to u-joints. They offer a much smoother transition when steering. And they spin 100% of the time due to lack of locking hubs...trade offs.

OR.... Mash the gas pedal and make all four wheels spin & slip. How tight you turn greatly effects this feedback too. The frt wheels are trying to take a much longer path than the rears when turning short but the T-case is locked up solid and forcing both frt & rear tires to spin the same speed. The frt tires are being pushed by the rears, and the rears are probably slipping.

FMC used to put slightly higher gear ratioes in the frt driving axle of 4X4's, like 3.50:1 in frt & 3.55:1 in rear, or 4.09:1 in frt and 4.11:1 in rear to allow the frt axle to "PULL" the rear when driving straight and reduce this pushing/pulling tendency on turns.

OR.... Mash the gas pedal and make all four wheels spin & slip. How tight you turn greatly effects this feedback too. The frt wheels are trying to take a much longer path than the rears when turning short but the T-case is locked up solid and forcing both frt & rear tires to spin the same speed. The frt tires are being pushed by the rears, and the rears are probably slipping.

FMC used to put slightly higher gear ratioes in the frt driving axle of 4X4's, like 3.50:1 in frt & 3.55:1 in rear, or 4.09:1 in frt and 4.11:1 in rear to allow the frt axle to "PULL" the rear when driving straight and reduce this pushing/pulling tendency on turns.

Actually when turning the inboard wheels to the turn will turn slower than the outside tires. The outside tires need to cover more ground faster than the inside of the turn tires do.

Actually when turning the inboard wheels to the turn will turn slower than the outside tires. The outside tires need to cover more ground faster than the inside of the turn tires do.

I don't believe Ford staggers axle ratios anymore (if they even did).

The difference in distance traveled from side-to-side is LESS than the difference front-to-back. Just look at the tracks your truck leaves on the ground. Longer the wheel base, the greater the difference. And the diff's in the axles compensate for side-to-side variations anyhow, No diff in the T-case so NO compensation frt to back.

And YES Ford did use different ratios. My '78 F150 had 3.55:1 in the 9-inch & 3.50:1 in the Dana 44 frt. My '87 & '96 PSD have the same thing.

The difference in distance traveled from side-to-side is LESS than the difference front-to-back. Just look at the tracks your truck leaves on the ground. Longer the wheel base, the greater the difference. And the diff's in the axles compensate for side-to-side variations anyhow, No diff in the T-case so NO compensation frt to back.

And YES Ford did use different ratios. My '78 F150 had 3.55:1 in the 9-inch & 3.50:1 in the Dana 44 frt. My '87 & '96 PSD have the same thing.

Actually I just measure exact wheel speed. This is a basic check when it comes to AWD issues. 4x4 systems are the same.

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